1. Field of the Invention
The present invention is directed to an x-ray tube, particularly for computer tomography (CT), having a cathode for generating an electron beam, a rotating anode having an incident area onto which the electron beam is incident in a focal spot, and deflection means for deflecting the electron beam dependent on an electrical deflection signal such that the focal spot periodically moves from a starting into a final position, preferably with a constant period.
2. Description of the Prior Art
X-ray tubes of the above type are employed for computer tomography since an improvement in the image quality can be achieved as a consequence of the periodic movement of the focal spot, by doubling the data available for calculating an image of a body slice. The deflection ensues such that the focal spot moves essentially in the circumferential direction of the rotating anode or tangentially relative to that circumferential direction.
Since the time required for generating an image of a body slice is extremely short as a consequence of progress achieved in the field of computer tomography and, moreover, the radiation dose administered to a patient in the preparation of an image is extremely low, the desire has recently arisen to be able to produce a plurality of images in immediate succession of the same body slice, or of body slices lying in extremely close proximity in order to thus improve the conditions for a reliable diagnosis. This, however, is only possible to a limited scope since there is a risk of overloading the x-ray tube employed.